Why Does Diesel Generator Fail to Start?
1. Failure phenomenon
a. No explosion sound in the cylinder, white smoke from the exhaust pipe;
b. Black smoke from the exhaust pipe.
Practice has proved that in order to maintain the smooth start of diesel generators, four necessary conditions must be met: a. It must have a certain speed; b. The oil and gas circuits must be unobstructed; C. The cylinders are well compressed; d. The fuel supply timing. From the above prerequisites for starting a diesel generator, it can be inferred that the diesel generator cannot start or is not easy to start.
2. Failure cause
Diesel engine speed is low; a. Starting speed is too low; b. Improper adjustment after pressure reducing device is not put into the correct position; c. Improper adjustment of valve clearance.
The oil and gas paths are not smooth; a. There is no diesel oil in the fuel tank, the oil pipeline is blocked, the fuel filter element is blocked, and oil switch is not open; b. When the diesel engine is started, the ambient temperature is too low; c. There is water or air in the oil path; d. The fuel injection nozzle is poorly sprayed or does not spray fuel; e. The air filter element is blocked or dirty.
Cylinder compression is not good; a. The clearance between the piston and cylinder wall is too large; b. The piston ring is broken or the elastic force is too small; c. The intake and exhaust valves are not closed tightly.
The fuel supply is not correct; a. The injection time is too early (it is easy to kill the injection pump) or too late; b. The valve distribution is not on time.
3. Inspection method
The failure should be carefully observed before inspection. For the diesel generator cannot start or start difficulty of this failure, it is usually judged and checked based on several different faults.
For diesel engines that use electric starting, if the starting speed is very slow, most of these faults are that the starting motor is weak, which does not mean that the diesel engine itself has a fault. It should be checked on the starting circuit to determine whether the battery has sufficient electricity, whether the wires are tightened well and whether the starter motor works well, and whether the air filter element is blocked.
The starting speed is normal, but cannot catch fire. There is no burst sound or intermittent burst sound from the cylinder, and the exhaust pipe emits white smoke. Through this phenomenon, it means that the diesel does not burn in the body and becomes steam exhaust or excessive moisture in the diesel oil.
First check whether the ambient temperature at the start of the diesel generator is too low, and then check whether there is air or moisture in the oil circuit.
The oil circuit joint of the diesel engine supply system is not tightly fixed, the needle valve of the fuel injection nozzle is stuck, and the diesel in the fuel tank has been used up before shutdown. This allows air to enter the diesel engine's supply system. In this way, when the plunger of the injector enters the diesel oil, the air entering the oil circuit is compressed, and the oil pressure cannot be increased. When the plunger of the injector enters the oil, the air volume expands and affects the oil absorption. As a result, the amount of diesel oil supply is suddenly increased or decreased.
The inspection method for this kind of failure phenomenon is to loosen the bleed screw on the diesel filter, the air bleed screw on the fuel injection pump or the high pressure oil pipe on the fuel injection pump, and rotate the diesel engine. If there are bubbles coming out, which indicates that there is air in the diesel engine supply system. The treatment method is to tighten the oil circuit joints, then loosen the air bleed screw on the fuel injection pump, turn the crankshaft until there is no bubble in the oil, and turn on the machine after tightening the bleeder screw. If moisture is found in the diesel oil, the same method can be used to check the cause of the moisture in the diesel oil. Replace the diesel in the fuel tank as required.
If there is no mixture of air and moisture in the diesel oil, should continue to check whether the injector performance is good and the fuel supply and distribution time is proper.